1. Field of the Invention
The present invention relates to a method for producing a spot size converter.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2001-127333 discloses a semiconductor light-receiving device. This semiconductor light-receiving device has a suitable structure for a high-speed operation. The semiconductor light-receiving device includes a light-detecting portion formed on a main surface of a substrate. The light-detecting portion includes an absorption layer that is composed of a semiconductor. The absorption layer receives light and generates a carrier in accordance with the intensity of the light. A waveguide is formed on the main surface of the substrate. The waveguide is optically coupled to the light-detecting portion. The waveguide guides light in a direction parallel to the main surface (waveguide direction) so that the light is incident on the absorption layer of the light-detecting portion. A photocurrent from the absorption layer of the light-detecting portion flows in the thickness direction of the absorption layer. Then, the photocurrent from the absorption layer is outputted to the outside through a pair of electrodes.